Martin Marietta Aggregates, 968 370th Ave, Grinnell, IA 50112, US

Martin Marietta Materials is one of the leading manufacturers of construction aggregates. It supplies crushed stone, sand and gravel used to build the roads, sidewalks and foundations. The company s products include asphalt, concrete and limestone used for flue gas desulfurization. Headquartered in Raleigh, North Carolina, Martin Marietta Materials also manufactures structural composite products for transportation, construction and military applications. Its composite truck bodies utilize TRANSONITE walls and floors that feature corrosion resistance and are used to develop matting and protective panels for military and commercial applications. The company s subsidiaries also manufacture magnesia-based chemical products.